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