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