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