I have two guinea pigs, and keep them safely away from my cats. I'm not sure the two species can co-exist absolutely safely- but I'm no expert. The few times my cats have been in close proximity to the pigs, they went directly into 'hunt mode'- crouched down- tails twitching, jaws chattering.
If I were you- I'd keep the piggies away from the cat.
Years ago I had a roommate who had a calico guinea pig and I had two cats, one of whom was a calico. Her guinea pig used to chase my calico cat all over the apartment! It was so funy to watch. We joked that the calico pig was chasing the calico cat because the pig thought the cat was his mommy!
I used to have guinea pigs and a cat, and never had a problem. Mind you, the cat in question is a female tonkinese who believes every furry thing smaller than her is a kitten in need of a new mommy! (this has included the pigs, my ferret, and various stuffed toys)