I am planning on fighting soon and just wondering if a potion of invisibilty would be a good thing to bring along.
The dragon doesn't dive bomb you when invisibility is in affect. However I've noticed it will throw magic bombs and dive bomb the last location arrows are shot from.
Way to win. Invisibility. Feather fall. Make a pillar. Shot crystals from pillar. Make way to enclosed crystals and destroy. Then kill dragon with arrows slowly.
In a way all the previous answers are right. The dragon cannot see you if you have the invisibility buff, provided you are wearing no armour and do nothing aggressive. As soon as you do anything that harms the dragon, including hitting the crystals, it will track you, and you will not last long without armour.
I found that at least some of the time if you destroy the crystals using redstone circuitry and TNT while invisible the dragon seems to fail to notice you. Maybe the few seconds to ignite the TNT is long enough to get away from the scene.
So, the way forward is to go into the end wearing no armour and with the invisibility buff. Do whatever you need to do to gain access to the crystals, mining obsidian, making a pillar or whatever. Just avoid hitting anything! When you are ready put on your armour and then the fun starts.