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