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)(25,26,31,35,30,33,36,39)(27,29,28,38,37,40,34,32)(1,3,4,7)(2,5,6,8)(9,11)(10,14)(12,18)(13,19)(15,21)(16,17)(20,24)(22,23)(25,27,30,37)(26,29,33,40)(28,36,34,31)(32,35,38,39)(2,6)(5,8)(9,12,13,20)(10,15,16,22)(11,18,19,24)(14,21,17,23)(25,28)(26,32)(27,36)(29,35)(30,34)(31,37)(33,38)(39,40)(11,19)(14,17)(18,24)(21,23)(26,33)(27,37)(28,34)(35,39) involution — undirected(10,16)(14,17)(15,22)(21,23)(25,29,31,38,30,40,36,32)(26,34,35,27,33,28,39,37)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.