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