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