diff --git a/tmap/tda/plot.py b/tmap/tda/plot.py
index 9aab6e5..4a03946 100644
--- a/tmap/tda/plot.py
+++ b/tmap/tda/plot.py
@@ -56,10 +56,13 @@ def __init__(self, target, dtype="numerical", target_by="sample"):
 
         if ((type(target[0][0]) != int)
                 and (type(target[0][0]) != float)
-                and (not isinstance(target[0][0],np.number))
+                and (not isinstance(target[0][0], np.number))
         ):
             self.label_encoder = LabelEncoder()
             self.target = self.label_encoder.fit_transform(target)
+        elif dtype == "categorical":
+            self.label_encoder = LabelEncoder()
+            self.target = self.label_encoder.fit_transform(target.astype(str))
         else:
             self.label_encoder = None
             self.target = target
@@ -191,14 +194,15 @@ def show(data, graph, color=None, fig_size=(10, 10), node_size=10, edge_width=2,
     legend_lookup = dict(zip(node_target_values.reshape(-1,), node_colors))
 
     # add categorical legend
-    if isinstance(color,Color):
+    if isinstance(color, Color):
         if color.dtype == "categorical":
             for label in set([it[0] for it in color.labels]):
                 if color.label_encoder:
-                    label_color = legend_lookup[color.label_encoder.transform([label])[0]]
+                    label_color = legend_lookup.get(color.label_encoder.transform([label])[0], None)
                 else:
-                    label_color = legend_lookup[label]
-                ax.plot([], [], 'o', color=label_color, label=label, markersize=10)
+                    label_color = legend_lookup.get(label, None)
+                if label_color is not None:
+                    ax.plot([], [], 'o', color=label_color, label=label, markersize=10)
             legend = ax.legend(numpoints=1, loc="upper right")
             legend.get_frame().set_facecolor('#bebebe')