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