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