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