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