One vertex per element, one color per generator, with an edge from x to x·s.
(3,7)(6,8)(10,13)(11,17)(16,21)(18,23)(25,26)(27,34)(28,31)(29,36)(30,33)(32,38)(35,37)(39,40) involution — undirected(1,2)(3,6)(4,5)(7,8)(9,10,14,13)(11,15,17,19)(12,16,20,21)(18,22,23,24)(26,28)(27,33)(32,36)(35,39)(2,5)(6,8)(12,20)(16,21)(18,23)(22,24)(25,27)(26,30)(28,34)(29,35)(31,33)(32,37)(36,40)(38,39) involution — undirected(9,11)(10,15)(12,18)(13,19)(14,17)(16,22)(20,23)(21,24)(25,28,31,26)(27,34,33,30)(29,36,38,32)(35,40,39,37)(1,2)(3,6)(4,5)(7,8)(9,12)(10,16)(11,18)(13,21)(14,20)(15,22)(17,23)(19,24)(25,29)(26,32)(27,35)(28,36)(30,37)(31,38)(33,39)(34,40) involution — undirected(1,3)(2,6)(4,7)(5,8)(9,13,14,10)(11,19,17,15)(12,21,20,16)(18,24,23,22)(25,30,31,34)(26,33,28,27)(29,37,38,40)(32,39,36,35)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.