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