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