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