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