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