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