In simple harmonic motion, kinetic energy is given by,

$K.E.=\frac{1}{2}k\left(A^2-d^2\right)$.

So, the graph is a downward parabola.

Here, $A=$amplitude of simple harmonic motion

and $d=$displacement from mean position in simple harmonic motion
and

$P.E.=\frac{1}{2}k{d}^2$.

So, the graph is an upward parabola.

At mean, $$\begin{gathered} d=0 \\ \Rightarrow K.E.=\frac{1}{2}K{A}^2 \end{gathered}$$

and potential energy is, $P.E.=0$.

At extreme positions,

$d=A\Rightarrow K.E.=0$.