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