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