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