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