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