I'd say the safest thing would be to not let them interact at all and to make sure the cage is as secure as possible. I've had my seemingly-uninterested cat (who is also usually as lazy as possible) knock over a glass gecko terrarium with dire consequences for one of my geckos. It happened during a small 5 minute window of time when I was moving and forgot to close the door of the room the geckos were kept in.

The cat may not intend to kill the reptile, but It could very well knock over a cage if not secured properly or cause a lid to cave in if it sat on the lid, etc.

When I have my snakes out, my cat is not allowed on the couch where I sit with them. He seems very interested, but he looks at them in the same manner that he looks at his "wand" toys... So I take that as a bad sign.

The smell of strange animals can also stress out some snakes, or cause others to strike (I've heard of boas showing feeding response to various animal scents), so I'd be leery of it for that reason too.

In the end it is your snake and your cat, but I'd highly advise that the cat not be left alone in the room with the snake cage unless the cage is extremely secure.