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