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