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