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