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