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