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