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