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