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