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