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