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