How to properly DEselect an item on RecyclerView?

I followed this answer: https://stackoverflow.com/a/30046476/8793443 and got it to work: only one item is selected at a time (which is what I want).

However, when the same item is clicked for a second time, it remains selected. How can I deselect it so that it goes back to it's original color background?

Any help is appreciated. Thanks!