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