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