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