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