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