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