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