Colors can hold just as much meaning on film as they do in a painting. In Jaws, Spielberg uses color as a hint, a warning, a reminder, etc. Sometimes this can be very straightforward. What would you guess red usually represents? (Hint: It ain't Valentine's Day.) Duh, there's lots of blood in Jaws. But it shows up in other places, too. Who wears red? Who sees red?
Other times, colors might be much more open to interpretation. For example, think of how many times bright yellow objects command our attention on-screen: barrels, lights, rafts, clothing, Brody's truck, sand on the beach, and more. In each situation yellow might suggest warmth (like sunshine), warning (like a caution sign), or any number of other things. What other color-coding can you find in Jaws?