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