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