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