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