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