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