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