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