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