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