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