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