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