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