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