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