diff --git a/lib/spack/spack/graph.py b/lib/spack/spack/graph.py
index 261d438e485..76ebbf636eb 100644
--- a/lib/spack/spack/graph.py
+++ b/lib/spack/spack/graph.py
@@ -531,7 +531,7 @@ def edge_entry(self, edge):
         return (
             edge.parent.dag_hash(),
             edge.spec.dag_hash(),
-            f"[color=\"{':'.join(colormap[x] for x in edge.deptypes)}\"]",
+            f"[color=\"{':'.join(colormap[x] for x in dt.flag_to_tuple(edge.depflag))}\"]",
         )