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