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