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