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