where is the motion path

Unfortunately, you cannot see the motion paths or easily edit them in the Contents section of a shape layer. When you have an effect with position coordinates, you can open the layer in the Layer Panel, select the effect, and view and edit motion paths in that panel. That workflow does not work with Shape Layer motion paths. 

A workaround would be to use the pen tool and draw the motion path you want to use for your star, set and then cut a keyframe for that path, and then select the Polystar/Transform Polystar position property and paste. This will give you the exact same motion path you drew as long as you have not moved or scaled the layer. 

Another option would be to use another layer to draw the motion paths you want on another layer, then use the Create Nulls From Paths script in the Window menu to create a null that traces a selected path. You can then use an expression in the shape layer to tie one of your stars to the position and then adjust the timing in the Effects Control Panel for the null.