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