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