Well,the 本 are really different from the show, In the 本 Elena is a Blonde and Bonnie's a red head,plus in the 表示する There are some charecters that have never been mentioned in the 本 and the opposite :)
she's been blonde since forever! the 表示する is based on the very 人気 book series. they've changed a bunch of things in the show, but it just makes it that much better and it's still awesome!