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