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