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