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