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