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)(26,33)(28,38)(29,39)(30,40)(31,44)(32,45)(34,47)(35,37)(36,50)(41,52)(42,53)(43,54)(46,55)(48,56)(49,51)(2,6)(3,7)(9,13,14,12)(10,17,18,16)(11,20,21,22)(15,23,19,24)(25,28,30,41)(26,34,32,46)(27,38,40,52)(29,43,31,42)(33,47,45,55)(35,49,36,48)(37,51,50,56)(39,54,44,53)(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.