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