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