One vertex per element, one color per generator, with an edge from x to x·s.
(5,6,12,16,11,18,10,17)(7,19,22,13,24,39,23,38)(8,25,28,42,30,14,29,43)(9,31,33,46,35,45,34,15)(20,47,26,54,50,40,49,36)(21,37,52,44,51,60,32,61)(27,56,59,41,58,65,57,53)(48,67,62,66,68,63,55,64)(1,2)(3,4)(5,7)(6,13)(8,26)(9,32)(10,23)(11,24)(12,22)(14,40)(15,44)(16,39)(17,19)(18,38)(20,29)(21,33)(25,47)(27,48)(28,50)(30,49)(31,60)(34,51)(35,52)(36,43)(37,45)(41,63)(42,54)(46,61)(53,67)(55,57)(56,66)(58,68)(59,62)(64,65) involution — undirected(2,4)(5,8,12,29,11,30,10,28)(6,14,17,43,18,25,16,42)(7,20,23,26,24,50,22,49)(9,27,34,59,35,58,33,57)(13,36,39,40,38,54,19,47)(15,41,31,56,46,53,45,65)(21,48,52,55,51,68,32,62)(37,63,61,64,60,67,44,66)(5,9,10,33,11,35,12,34)(6,15,16,45,18,46,17,31)(7,21,22,32,24,51,23,52)(8,27,28,57,30,58,29,59)(13,37,19,44,38,60,39,61)(14,41,42,65,25,53,43,56)(20,48,49,62,50,68,26,55)(36,63,47,66,54,67,40,64)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.