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