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