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