How to make dog leave cat alone?

I'm having trouble making Kayla stay away from Momma Cat. She loves cats, she follows her around, tail wagging, and pants in her face and licks her. Momma cat tolerates some of it but eventually sticks her claws in Kayla's face when she's had enough (I don't blame her, doggy breath is yuck). I thought after a few cat swats Kayla would learn to stay way but she doesn't. She doesn't even notice when Momma is hanging off her with her claws sunk in Kayla's cheek and I have to run over and unattached them (Kayla just standing calmly tail wagging through the whole ordeal). I'm glad Kayla loves cats so much but am worried she is going to get her eye scratched one day. How can I teach her to love them but stay away from them?

The "leave it" command always works best for us. When Briggs tends to play a little rough with Connor I was tell her "Leave it" as a sign that it's enough.. ("enough" works too).

We first taught her this trick with a treat on the ground in front of her. And tell her "leave it". As she goes to take it, make sure that you get it first. Then put it down in front of her again and say leave it. Once they actually leave it alone, then when they do, let them have it.