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