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