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