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