BUG: addresses #14855 by fixing color kwarg conflict

Author: alexandercbooth

pandas/tools/plotting.py

@@ -359,7 +359,10 @@ def scatter_matrix(frame, alpha=0.5, figsize=None, ax=None, grid=False,
     density_kwds = density_kwds or {}
 
     # workaround because `c='b'` is hardcoded in matplotlibs scatter method
-    kwds.setdefault('c', plt.rcParams['patch.facecolor'])
+    if 'color' in kwds:
+        pass
+    else:
+        kwds.setdefault('c', plt.rcParams['patch.facecolor'])
 
     boundaries_list = []
     for a in df.columns: