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