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)(27,30)(28,31)(29,34)(32,38)(33,35)(36,40)(37,39)(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)(26,27)(28,35)(32,34)(36,37)(43,49)(46,53)(50,55)(54,56)(9,10)(11,15)(12,16)(13,14)(17,20)(18,22)(19,21)(23,24)(25,27,30,26)(28,33,35,31)(29,34,38,32)(36,40,37,39)(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)(25,28,30,35)(26,31,27,33)(29,37,38,36)(32,40,34,39)(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)(25,29)(26,32)(27,34)(28,36)(30,38)(31,39)(33,40)(35,37)(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.