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