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