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