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