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