Create a new palette section containing the node templates you want to use in your graph. For each of the node templates, set the Label Insets to "0 40 0 40" or whatever values you find appropriate to force additional spacing on the left and right of the label for that shape. The 4 values represent top, left, bottom, and right insets. Use the properties mapper to assign the node templates as you did before, using the new templates with the label insets. Some of the labels may still overlap the node shapes. Use "Tools" --> "Fit Node to Label" to resize the nodes. The label insets should now prevent the label text from overlapping the node shapes.