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