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