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