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