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