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