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