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