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