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