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