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