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