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