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