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