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