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