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