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