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