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