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