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