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