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