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