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