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