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