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