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