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