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