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