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