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