diff --git a/src/tree/tree_model.cc b/src/tree/tree_model.cc
index 040022c373a4..0639233510f7 100644
--- a/src/tree/tree_model.cc
+++ b/src/tree/tree_model.cc
@@ -303,9 +303,8 @@ class TextGenerator : public TreeGenerator {
     return result;
   }
 
-  std::string SplitNodeImpl(
-      RegTree const& tree, int32_t nid, std::string const& template_str,
-      std::string cond, uint32_t depth) const {
+  std::string SplitNodeImpl(RegTree const& tree, bst_node_t nid, std::string const& template_str,
+                            std::string cond, uint32_t depth) const {
     auto split_index = tree[nid].SplitIndex();
     std::string const result = SuperT::Match(
         template_str,
@@ -345,18 +344,16 @@ class TextGenerator : public TreeGenerator {
     return SplitNodeImpl(tree, nid, kNodeTemplate, ToStr(cond), depth);
   }
 
-  std::string Categorical(RegTree const &tree, int32_t nid,
-                       uint32_t depth) const override {
+  std::string Categorical(RegTree const& tree, bst_node_t nid, uint32_t depth) const override {
     auto cats = GetSplitCategories(tree, nid);
     std::string cats_str = PrintCatsAsSet(cats);
     static std::string const kNodeTemplate =
         "{tabs}{nid}:[{fname}:{cond}] yes={right},no={left},missing={missing}";
-    std::string const result =
-        SplitNodeImpl(tree, nid, kNodeTemplate, cats_str, depth);
+    std::string const result = SplitNodeImpl(tree, nid, kNodeTemplate, cats_str, depth);
     return result;
   }
 
-  std::string NodeStat(RegTree const& tree, int32_t nid) const override {
+  std::string NodeStat(RegTree const& tree, bst_node_t nid) const override {
     static std::string const kStatTemplate = ",gain={loss_chg},cover={sum_hess}";
     std::string const result = SuperT::Match(
         kStatTemplate,
@@ -679,15 +676,12 @@ class GraphvizGenerator : public TreeGenerator {
     std::string result;
     if (this->with_stats_) {
       CHECK(!tree.IsMultiTarget()) << MTNotImplemented();
-      result = SuperT::Match(
-          kNodeTemplate, {{"{nid}", std::to_string(nidx)},
-                          {"{fname}", GetFeatureName(fmap_, split_index)},
-                          {"{<}", has_less ? "<" : ""},
-                          {"{cond}", has_less ? ToStr(cond) : ""},
-                          {"{stat}", Match("\ncover={cover}\ngain={gain}",
-                                           {{"{cover}", std::to_string(tree.Stat(nidx).sum_hess)},
-                                            {"{gain}", std::to_string(tree.Stat(nidx).loss_chg)}})},
-                          {"{params}", param_.condition_node_params}});
+      result = SuperT::Match(kNodeTemplate, {{"{nid}", std::to_string(nidx)},
+                                             {"{fname}", GetFeatureName(fmap_, split_index)},
+                                             {"{<}", has_less ? "<" : ""},
+                                             {"{cond}", has_less ? ToStr(cond) : ""},
+                                             {"{stat}", this->NodeStat(tree, nidx)},
+                                             {"{params}", param_.condition_node_params}});
     } else {
       result = SuperT::Match(kNodeTemplate, {{"{nid}", std::to_string(nidx)},
                                              {"{fname}", GetFeatureName(fmap_, split_index)},
@@ -703,9 +697,15 @@ class GraphvizGenerator : public TreeGenerator {
     return result;
   };
 
-  std::string Categorical(RegTree const& tree, bst_node_t nidx, uint32_t) const override {
+  std::string NodeStat(RegTree const& tree, bst_node_t nidx) const override {
+    return Match("\ngain={gain}\ncover={cover}",
+                 {{"{cover}", std::to_string(tree.Stat(nidx).sum_hess)},
+                  {"{gain}", std::to_string(tree.Stat(nidx).loss_chg)}});
+  }
+
+  std::string Categorical(RegTree const& tree, bst_node_t nidx, uint32_t /*depth*/) const override {
     static std::string const kLabelTemplate =
-        "    {nid} [ label=\"{fname}:{cond}\" {params}]\n";
+        "    {nid} [ label=\"{fname}:{cond}{stat}\" {params}]\n";
     auto cats = GetSplitCategories(tree, nidx);
     auto cats_str = PrintCatsAsSet(cats);
     auto split_index = tree.SplitIndex(nidx);
@@ -714,6 +714,7 @@ class GraphvizGenerator : public TreeGenerator {
         SuperT::Match(kLabelTemplate, {{"{nid}", std::to_string(nidx)},
                                        {"{fname}", GetFeatureName(fmap_, split_index)},
                                        {"{cond}", cats_str},
+                                       {"{stat}", this->NodeStat(tree, nidx)},
                                        {"{params}", param_.condition_node_params}});
 
     result += BuildEdge<true>(tree, nidx, tree.LeftChild(nidx), true);
diff --git a/tests/cpp/tree/test_tree_model.cc b/tests/cpp/tree/test_tree_model.cc
index 941c425bd9b0..2491f3973f9a 100644
--- a/tests/cpp/tree/test_tree_model.cc
+++ b/tests/cpp/tree/test_tree_model.cc
@@ -340,6 +340,7 @@ void TestCategoricalTreeDump(std::string format, std::string sep) {
   ASSERT_NE(pos, std::string::npos);
   pos = str.find(cond_str, pos + 1);
   ASSERT_NE(pos, std::string::npos);
+  ASSERT_NE(str.find("gain"), std::string::npos);
 
   if (format == "json") {
     // Make sure it's valid JSON