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