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