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