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