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