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