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)(12,17)(13,22)(14,15)(16,21)(19,24)(20,23)(25,26,32,35)(27,36,38,33)(28,30,29,39)(31,34,40,37)(2,5)(6,7)(10,15)(12,22)(16,18)(19,23)(25,27)(26,33)(28,34)(29,37)(30,31)(32,38)(35,36)(39,40) involution — undirected(1,2)(3,6)(4,5)(7,8)(10,15)(13,17)(16,18)(20,24)(25,28,32,29)(26,30,35,39)(27,34,38,37)(31,36,40,33)(1,3,4,8)(2,6,5,7)(9,11,14,21)(10,16,15,18)(12,23,22,19)(13,20,17,24)(25,29,32,28)(26,30,35,39)(27,37,38,34)(31,36,40,33)(9,12)(10,17)(11,19)(13,15)(14,22)(16,20)(18,24)(21,23)(25,30)(26,29)(27,31)(28,35)(32,39)(33,37)(34,36)(38,40) involution — undirected(9,13,14,17)(10,12,15,22)(11,20,21,24)(16,23,18,19)(25,31)(26,34)(27,30)(28,33)(29,36)(32,40)(35,37)(38,39)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.