[Tex/LaTex] How to draw this vector diagram in latex

Question

I tried tikzpicture, but the arrow is too thin. also, I don't know how to draw the coordinate system, and put the label at the end of the arrow.

\begin{tikzpicture}

    \draw[->, ultra thick, blue,  arrows={-latex}]  (0,0) -- (1,1) node[sloped,midway,above=-0.1cm] {$\mathsf{v}$};

\end{tikzpicture}

Answer 1

\documentclass{article}
\usepackage{tikz}
\usepackage{amsmath}
\begin{document}
\begin{tikzpicture}
  \draw[thin,gray!40] (-2,-2) grid (2,2);
  \draw[<->] (-2,0)--(2,0) node[right]{$x$};
  \draw[<->] (0,-2)--(0,2) node[above]{$y$};
  \draw[line width=2pt,blue,-stealth](0,0)--(1,1) node[anchor=south west]{$\boldsymbol{u}$};
  \draw[line width=2pt,red,-stealth](0,0)--(-1,-1) node[anchor=north east]{$\boldsymbol{-u}$};
\end{tikzpicture}
\end{document}