How to represent a switch "tabbed" state in Material Design?

Trying to determine a way to represent a "tabbed" state on a switch that looks like this:

Under the hood, it is just a checkbox that the user can tab-over and press enter to check/uncheck the box.

What is a way that I can represent the active tabbed state on the switch specifically?

I have tried to add an outline/box-shadow, but I am using material design guidelines and don't think this works with the clean-cut active states on text inputs etc.