Ender Dragons cannot be teleported relatively, to specific coordinates, nor to a player/entity using the following commands:

/tp @e[type=EnderDragon] ~ ~10 ~
/tp @e[type=EnderDragon] 0 10 0
/tp @e[type=EnderDragon] <Playername>

This may be on purpose but I feel as though the implementation of the ability to teleport Ender Dragons would further mapmaker's abilities in many situations. Thank you for your time.