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