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