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