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