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