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