There are three distinct Power Girl costumes. The one you did is from her JLA/JLE appearances, and the latest GL story. Most of the time she's been seen in a plain scoop-neck white leotard with belt, boots, gloves, and cape. That one is derived from the original Wally Wood costume design from the 70's JSA revival where the leotard had a high neck and a circular cutout over her cleavage, and the belt was a hip-hugger. With this costume her hairstyle was more of a bubble-cut. She's always been quite buxom, showing her origins as a Wally Wood character creation. She started off as the Earth-2 Supergirl, but after the Crisis was revealed to be the grand-daughter of Arion of atlantis, kept in mystical suspended animation for several thousand years.