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)(11,14,17,20)(12,15,19,22)(18,21,23,24)(25,26)(27,36)(28,33)(29,34)(30,39)(31,35)(32,37)(38,40)(9,11)(10,14)(12,18)(13,17)(15,21)(16,20)(19,23)(22,24)(25,27,30,37,31,38,29,33)(26,32,34,36,35,28,39,40)(2,5)(6,8)(11,17)(14,20)(18,23)(21,24)(25,28)(26,33)(27,34)(29,36)(30,40)(31,32)(35,37)(38,39) involution — undirected(1,3,4,7)(2,6,5,8)(9,12)(10,15)(11,18)(13,19)(14,21)(16,22)(17,23)(20,24)(25,29,31,30)(26,34,35,39)(27,37,38,33)(28,36,32,40)(12,19)(15,22)(18,23)(21,24)(25,29,31,30)(26,34,35,39)(27,33,38,37)(28,40,32,36)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.