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