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