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