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