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