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