会 would mean "have the ability". So 你会开车吗？ would literally mean Do you have the ability to drive a car? which can be translated as Can you drive a car? but in case of party you don't ask if someone has ability, but rather if he/she is allowed/wants to come
If you used 会 in its place, the meaning would be closer to "will you be coming to my party" or "are you going to come to my party?" Similar meaning, but in this case we are asking "can you" (physcially able to).