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