Not really – you can’t prepare for a personality test any more than you can change who you are! There are no right or wrong answers in these tests, only honest or dishonest ones. And the experts (occupational psychologists) who structure these tests and evaluate the answers can usually tell if you are being a bit shifty. All you can really do is promise yourself to be honest, and not try to second-guess what you think the employer wants (not least because you really don’t know what that is).
A properly conducted personality test is just trying to find out more information about you so that managers can take better decisions. If that means you’re a good match for the job and the employer, great. If not, maybe you had a lucky escape.