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