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