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