Ah! "Sketch a
graph." That makes a lot more sense!
Take the bounds they've given you, lightly sketch a rectangle enclosing these bounds, and then draw any curve you like that touches all four sides. Just make sure that the curve doesn't turn back on itself sideways, because then it wouldn't represent a function.
The simplest graph would probably be a straight line from one left-hand corner to the opposite right-hand corner.