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