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