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