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