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