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