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