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