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