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