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