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