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