Point $P$ moves along the unit circle (circle with radius $1$). The corresponding angle of rotation $\alpha$ is positive when you move counterclockwise, negative if when you move clockwise. It can have any value. The height $h$ of $P$ with respect to the horizontal axis is $h=sin\left(\alpha \right)$.
For a more suitable graph we rather express the angle of rotation $\alpha =x$ in radians.
$360°$ correponds to $2\pi$ radians.
This standard sine graph is periodical with period $2\pi$.