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