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