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