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