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