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