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