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)(11,18)(12,20)(13,15)(14,17)(16,21)(19,23)(22,24)(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)(9,11,14,13)(10,15,17,18)(12,19,21,22)(16,23,20,24)(27,33)(30,37)(34,39)(38,40)(1,2)(3,5)(4,6)(7,8)(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)(10,16)(11,19)(13,22)(14,21)(15,23)(17,20)(18,24)(25,26)(27,30)(28,31)(29,32)(33,37)(34,38)(35,36)(39,40)(9,13,14,11)(10,15,17,18)(12,19,21,22)(16,24,20,23)(25,27,29,33)(26,30,32,37)(28,34,36,39)(31,38,35,40)(9,10)(11,15)(12,16)(13,18)(14,17)(19,23)(20,21)(22,24)(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.