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