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