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