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