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