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