documentclass[tikz]{standalone}
usepackage{pgfplots,mathtools}
usepackage{filecontents}
usepgfplotslibrary{fillbetween}
usepackage{amsmath,amssymb,bm}
pgfplotsset{compat=newest}

begin{document}

pgfplotstableread{results.dat}{Results}

begin{tikzpicture}[]
    begin{axis}[width=columnwidth,
        height=0.618columnwidth,
        ymode=log,
        xlabel style = {font=Large, yshift=0.5ex},
        ylabel style = {font=Large, yshift=-1.1ex},
        xlabel={SNR (text{dB})},
        ylabel={MSE (text{rad}$^2$)},
        xmin=-40, xmax=15,
        axis line style={line width=1pt},
        xticklabel style = {font=Large,yshift=-0.2ex},
        yticklabel style = {font=Large,xshift=-0.2ex},
        xtick={-40,-30,-20,-10,0,10},
        xticklabels={-40,-30,-20,-10,0,10},
    ]
    addplot [black, line width=1pt] table [x={x}, y={s}] {Results};
end{tikzpicture}

end{document}

x  s
 -40.   4.032258064516129
 -39.99 4.022984128316752
 -39.98 4.013731521578736
 -39.97 4.004500195245699
 -39.96 3.9952901003740666
 -39.95 3.9861011881328228
 -39.94 3.976933409803266
 -39.93 3.967786716778768
 -39.92 3.958661060564457
 -39.91 3.949556392777008
 -39.9  3.9404726651444
 -39.89 3.9314098295055957
 -39.88 3.922367837810347
 -39.87 3.9133466421189103
 -39.86 3.9043461946018128
 -39.85 3.8953664475395726
 -39.84 3.8864073533224652
 -39.83 3.8774688644502615
 -39.82 3.86855093353199
 -39.81 3.8596535132856657
 -39.8  3.850776556538048
 -39.79 3.8419200162244036
 -39.78 3.833083845388234
 -39.77 3.8242679971810394
 -39.76 3.815472424862069
 -39.75 3.8066970817980788
 -39.74 3.7979419214630714
 -39.73 3.789206897438054
 -39.72 3.7804919634108067
 -39.71 3.771797073175613
 -39.7  3.763122180633034
 -39.69 3.7544672397896375
 -39.68 3.7458322047578068
 -39.67 3.737217029755445
 -39.66 3.728621669105734
 -39.65 3.7200460772369466
 -39.64 3.7114902086821457
 -39.63 3.7029540180789593
 -39.62 3.6944374601693513
 -39.61 3.6859404897993984
 -39.6  3.677463061918994
 -39.59 3.6690051315816636
 -39.58 3.6605666539442985
 -39.57 3.6521475842669378
 -39.56 3.6437478779125088
 -39.55 3.635367490346601
 -39.54 3.62700637713724
 -39.53 3.618664493954633
 -39.52 3.6103417965709457
 -39.51 3.602038240860062
 -39.5  3.593753782797362
 -39.49 3.5854883784594715
 -39.48 3.5772419840240355
 -39.47 3.5690145557694977
 -39.46 3.5608060500748504
 -39.45 3.5526164234194137
 -39.44 3.544445632382597
 -39.43 3.5362936336436888
 -39.42 3.528160383981598
 -39.41 3.520045840274642
 -39.4  3.5119499595003245