The cassette looks fine (to me). First make sure that you threaded the chain through the rear derailleur correctly. It's easy to accidentally have the chain running outside of the cage a little bit -- there are little metal tabs the backside of the arm of the derailleur that you might not have threaded the chain inside, which would then constantly rub the chain. That would cause a lot of noise.

You might also have gotten your derailleur(s) out of adjustment while cleaning, and you should refer to the parktool.com website for tips on derailleur adjusment.