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