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