Notice that the electric field vectors create a wave. The wave decays proportionally to $\frac{1}{r}$, where $r$ is the distance from the charge. The electric field vectors behave differently in the two coordinate systems. In the upper one, the field is exactly like it is in real life. The equation $$\mathbf{E} = \frac{q}{4\pi\epsilon_0} \left[ \frac{\mathbf{e}_{\mathbf{r}'}}{r^{\prime 2}} + \frac{\mathbf{r}'}{c} \frac{d}{dt}\left(\frac{\mathbf{e}_{\mathbf{r}'}}{r^{\prime 2}}\right) + \frac{1}{c^2} \frac{d^2}{dt^2} \mathbf{e}_{\mathbf{r}'} \right]$$ describes it perfectly. It is noticeable that near the charge, the terms that are proportional to $\frac{1}{r^2}$ "overpower" the radiation term (the third one, which scales as $\frac{1}{r}$) Because of this, the vectors there are very long and point mostly away from the charge (similar to Coulomb's law). But as the distance increases, the $\frac{1}{r^2}$ terms fade away faster, and the vectors point mostly in the vertical direction, forming a wave. In the lower coordinate system, the electric field is approximated based on the equation $$E_y(t) = \frac{q}{4\pi\epsilon_0 c^2 r} a_y\left(t - \frac{r}{c}\right).$$ This of course ignores any terms that scale as $\frac{1}{r^2}$, so it is very wrong as we get close to the charge. But further away, it starts to be very similar to the electric field in the upper coordinate system, as the approximation gets better and better.

In the lower coordinate system the electric field vectors never go above the light blue plot. That is because that plot is a visualization of the function $$\frac{q}{4\pi\epsilon_0 c^2 x} A \omega ^2.$$ Why is that the function? Of course, the first part comes from the approximated electric field formula. The $A \omega ^2$ then corresponds to $a_y\left(t - \frac{r}{c}\right)$, but the charge undergoes simple harmonic motion, so its acceleration is $$A \omega ^2 \cos(\omega t).$$ The maximum value of $\cos(\omega t)$ is $1$, so the maximum value of the acceleration is simply $A \omega ^2$, used for the plots. The electric field in the upper coordinate system sometimes goes above the function, because of course the approximation gets worse and worse as we go near the charge.