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