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