I just wanted to mention that with the possible exception of Nidalee, your team had entirely AD damage, meaning that the enemy team should have been able to mitigate a lot of your early lead in later fights just by purchasing armor.
As for advice, when running with a composition like that your best bet is to force disadvantageous fights on your opponents by drawing the enemy team out with split-pushing and catching an opponent or two alone to make fights a 5v4 or 5v3. Never fight head on, and make sure you have an ally with oracles and a sightstone to win the vision wars necessary for split-pushing. Once you have the numerical advantage you can choose to either pursue the rest of their team or to continue pushing. Better yet, if you can kill off one or two of the remaining enemy team members and keep their death timers out of sync with each other so that they are a constant number disadvantage your game should be in the bag.
Oh, and as a side note, Aatrox functions well as a tank so a possible mistake on your part may have been building as a carry from your early lead instead of transitioning into the tank/off-tank your team would need later for teamfights. With aatrox's mobility, potential tankiness, and superior damage, you can effectively zone a behind team's carries out of a teamfight so that your "hard-carries" can do their work. I'm not saying you shouldn't build damage on Aatrox, but in this particular situation itemizing for tankiness might have been a good decision.