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