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