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