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