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