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