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