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