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