Cerberus uses all three combat styles to attack you. So you will have to use the style that you are the weakest against. I would advise you to use range to kill Cerberus. This is for two reasons. First, when you fight Cerberus with range, there is a nice distance between the two of you. Cerberus will not come closer and will only attack with range and magic. This means you do not have to take into account Cerberus her melee attacks anymore. Second, using range is going to give you a massive boost against magic attacks due to the gear you are wearing. So your weak point will be Cerberus her ranging attacks. In short, when using the range, you should pray for range protection against Cerberus.