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