Use Haiku's Shortcuts preferences to set a key combination for the tool.
Just run it to see the effect.
To change settings like number of circles, their width and the speed of the animation, run it from the Terminal with the -s parameter:
WhereIsMyMouse -s
This will open a settings panel to adjust those visuals. You can change the color of the circles by drag'n'dropping a color from an app like Colors!, Icon-O-Matic or WonderBrush onto the animation preview.
Settings are saved in ~/config/settings/WhereIsMyMouse_settings.