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