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