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