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