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