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