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