YAY! This is probably the first Metal Fighter fan art I've EVER seen! I've seen all the episodes at least 4 times so I'll try to fill you in on Sayaka's personality.
Sayaka's the pretty girl of the Pretty Four (Oo). She likes to wear make-up and be the prettiest girl in Japan. She's really weak in the ring (comparred to the others) and she usually tries to hide her weakness by commenting things like "I should have been paying more attention" or "She got my weak spots", and stuff like that. She loves guys and wants to find "the perfect man" for her. She's single through the entire series and it really doesn't mention her ever being romantically in love with anyone. When it comes to how she dresses, she likes to wear less, and show more (although, you really only see her in real clothes a couple times). Yeah, I don't really know what else there is to say about her.
I hope this helps at all!
Yay, spiffy hair! Would you people comment on the darn images! Sheesh... Ayame doesn't need to hear me over and over again...