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