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