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