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