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