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