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