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