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