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