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