Build a 3 by 3 stone pillar taming pen that is 2 pillars high. Put one pillar (2 high) in the middle with and leave one side open (without one 2 High pillar) to kite the griffin in. Lead the griffin under the ceiling and into the pillars with a pteranadon (which can fly through pillars) and place pillars behind him to trap.
Before you all go naming your griffins "Buckbeak" lemme lay some mythology on ya. Buckbeak from Harry Potter was actually a hippogriff which is a horse combined with a eagle. A griffin is a lion combined with an eagle. Just keep this in mind before going on a Buckbeak naming spree.