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