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