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