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