We know that the object is moving at 5m/s already telling us that the distance the object has travelled increases with time. Plotting distance on the y axis against time on the x axis we therefore expect a straight line that increases linearly with time. Using distance = speed * time, we can label how far the object has travelled on the y axis (50m). The speed-time graph will be a horizontal straight line as the object is travelling with constant velocity throughout its motion. Constant velocity also tells us that the the object is not accelerating so the acceleration-time graph would be a horizontal straight line at 0m/s2.
For a stronger student who has started to expose themselves to some AS Level Mathematics this could be a good introduction to the principles of differentiation and integration applied to physical scenarios.