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