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