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