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