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