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