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