It depends on the age of the cat. If the cat is fairly young (less than 2 years), I would suggest caution as the cat is likely to simply view the snake as another plaything.
If the cat is older, I would suggest this approach...
1. place the snake in a cloth snakebag. Let the cat smell the snake through the bag.
2. place the snake on the floor next to the cat. If the cat starts pawing roughly at it, tell the cat no (in spite of what most people think, cats are very capable of learning simple commands like dogs). If it continues, save the snake.
3. Then let the cat watch you put the snake back in its aquarium.
With time, the cat will become bored with the snake and stop paying attention to it. Most of the problems people have with cats and snakes is that the cats are curious. Once you satisfy their curiosity, they will move on to something else.
I have had cats and snakes for over 20 years, and have never had a problem. My cats pay no attention to my snakes (although they are good at finding them for me if they escape!).
-----
Chris Harrison