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