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