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)(27,33)(28,39)(29,35)(30,36)(31,40)(32,37)(34,38)(1,2)(3,7)(4,6)(5,8)(9,11,13,19)(10,14,16,17)(12,20,21,18)(15,23,24,22)(25,27)(26,33)(28,31)(29,30)(32,38)(34,37)(35,36)(39,40)(1,3)(2,5)(4,8)(6,7)(25,28)(26,34)(27,31)(29,32)(30,38)(33,37)(35,36)(39,40) involution — undirected(3,8)(5,7)(9,12,13,21)(10,15,16,24)(11,18,19,20)(14,22,17,23)(25,29,32,28)(26,35,37,39)(27,30,38,31)(33,36,34,40)(2,6)(5,7)(10,16)(14,17)(15,24)(22,23)(25,30,32,31)(26,36,37,40)(27,28,38,29)(33,39,34,35)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.