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