Since f'(2)=0, there is a stationary point when x=2.
Since f'(x)>0 for x<2, the gradient is positive for any x-value less than 2 (so that it slopes to the right).
Since f'(x)<0 when x>2, the gradient is negative for any x-value greater than 2 (so that is slopes to the left).
Sketching this...