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