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