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)(25,26)(27,34)(28,33)(29,31)(30,38)(32,36)(35,40)(37,39)(1,2)(3,7)(4,6)(5,8)(9,11)(10,14)(12,19)(13,18)(15,22)(16,17)(20,23)(21,24)(26,31)(27,35)(33,38)(36,37) involution — undirected(1,3)(2,5)(4,8)(6,7)(25,27,28,37,29,35,30,36)(26,32,38,40,31,39,33,34)(2,6)(3,8)(11,18)(14,17)(19,24)(22,23)(25,28,29,30)(26,33,31,38)(27,36,35,37)(32,40,39,34)(2,6)(5,7)(9,12,13,21)(10,15,16,20)(11,19,18,24)(14,22,17,23)(26,31)(32,39)(33,38)(34,40)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.