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