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