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