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