Hi Roy 

Thank you for reaching out to the community! There is currently not a way to set up a hotspot to change color when you are toggling on and off layers. The gif I attached shows another shape the same size as the button I created that is associated with the changing layer. When turned off the original button labeled "off" shows and vice versa. (Like you mentioned as your workaround) For now while not a perfect solution this would be the best way to move forward. You will also see in your layers panel that the eye icon turns off and on. This can be a good way to reference which layers are currently showing or hidden! 

We're always looking for ways to improve Lucidchart and your feedback about this hotspot feature is the best way for us to do that. Would you mind adding your idea to our feature request form? Ideas submitted to this form are passed on to the product development team for their consideration.

Emma - thanks for taking the time to reply. Very helpful and I'll move forward with your recommended approach as that meets the need. I think this could be a useful UI feature and I'll take the time to submit the request form per your note.

Cheers.

-Roy