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