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