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