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