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