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