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