One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,3,4)(5,6,11,18,12,16,10,17)(7,19,23,38,24,13,22,39)(8,25,29,14,30,43,28,42)(9,15,34,45,33,47,35,46)(20,40,51,48,52,62,26,36)(21,49,55,63,54,37,31,44)(27,56,58,41,32,60,59,66)(50,64,68,65,53,67,57,61)(5,7,12,24)(6,13,16,19)(8,26,30,51)(9,31,33,55)(10,23,11,22)(14,40,42,62)(15,44,47,63)(17,39,18,38)(20,29,52,28)(21,34,54,35)(25,48,43,36)(27,53,32,50)(37,46,49,45)(41,65,66,61)(56,67,60,64)(57,58,68,59)(5,8,12,30)(6,14,16,42)(7,20,24,52)(9,32,33,27)(10,29,11,28)(13,36,19,48)(15,41,47,66)(17,43,18,25)(21,53,54,50)(22,51,23,26)(31,57,55,68)(34,58,35,59)(37,61,49,65)(38,40,39,62)(44,67,63,64)(45,56,46,60)(5,9,10,35,12,33,11,34)(6,15,17,46,16,47,18,45)(7,21,22,31,24,54,23,55)(8,27,28,59,30,32,29,58)(13,37,38,63,19,49,39,44)(14,41,25,56,42,66,43,60)(20,50,26,57,52,53,51,68)(36,61,62,67,48,65,40,64)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.