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