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