"Ch" in pinyin is a slightly different sound to "c". C is closer to a ts or tsh. You will get a better feel for the difference between the consonant sounds by listening to recordings of 茝 (chǎi) and 彩 (cǎi) being pronounced.
However, the pronunciation of the name as a whole is contingent on what actual characters you use, because Mandarin is a tonal language, so for example cái (才) means "talent" while 彩 (cǎi) means "colour".