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