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)(27,38)(28,34)(29,47)(30,48)(31,37)(32,35)(33,41)(36,40)(39,54)(42,52)(43,56)(44,50)(45,53)(46,51)(49,55) 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)(26,33)(28,42)(29,40)(30,32)(31,41)(34,50)(35,36)(37,38)(39,46)(43,55)(44,45)(47,48)(49,51)(52,53)(54,56)(2,6)(5,8)(9,12,13,20)(10,15,16,22)(11,18,19,24)(14,21,17,23)(25,28,29,43,31,45,32,46)(26,34,47,56,37,53,35,51)(27,39,30,44,41,55,40,42)(33,49,36,52,38,54,48,50)(10,16)(14,17)(15,22)(21,23)(25,29,31,32)(26,35,37,47)(27,40,41,30)(28,43,45,46)(33,36,38,48)(34,51,53,56)(39,42,55,44)(49,52,54,50)(11,19)(14,17)(18,24)(21,23)(25,30,32,27,31,40,29,41)(26,36,35,33,37,48,47,38)(28,44,46,39,45,42,43,55)(34,52,51,49,53,50,56,54)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.