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