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