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