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