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