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