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