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