What color rose means you are sorry?

There is no rose color that specifically represents an apology. However, there are some colors that have meanings which might enforce the message of "I'm Sorry".

Yellow represents "Friendship" and "Joy" and is even recognized by some as being an appropriate apology color.

White represents "Innocence", "Humility", and "Purity"

Peach can mean "Sincerity"

Pink can mean "Gentleness" and "Please Believe Me"

And, of course, the color you should choose also depends on your relationship with the person you are giving them to. For example, Red usually means deep romantic love, so you wouldn't want to give that color to someone who is just a friend.

At the end of the day, though, all symbolism aside, any rose bouquet of any color accompanied with a real, sincere apology will probably deliver the message quiet adequately.