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