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