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