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