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