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)(11,18)(12,15)(13,16)(14,17)(19,22)(20,23)(21,24)(25,26,31,36)(27,30,35,32)(28,33,38,40)(29,39,37,34)(2,4)(6,7)(10,12)(11,16)(17,20)(19,24)(25,27)(26,32)(28,37)(29,38)(30,36)(31,35)(33,39)(34,40) involution — undirected(1,3)(2,6)(4,7)(5,8)(9,11)(10,13)(12,18)(14,19)(15,16)(17,21)(20,22)(23,24)(25,28,31,38)(26,33,36,40)(27,37,35,29)(30,34,32,39)(1,4,5,2)(3,7,8,6)(9,12,15,10)(11,18,16,13)(14,20,23,17)(19,22,24,21)(25,29,31,37)(26,34,36,39)(27,38,35,28)(30,33,32,40)(9,13,15,18)(10,16,12,11)(14,22,23,21)(17,19,20,24)(25,27)(26,30)(28,37)(29,38)(31,35)(32,36)(33,34)(39,40)(9,14,15,23)(10,17,12,20)(11,19,16,24)(13,21,18,22)(25,30)(26,35)(27,36)(28,34)(29,33)(31,32)(37,40)(38,39)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.