OK, you're almost there. Your temperature is around 78 and the scale of the graph for the server starts at 90 and goes 115 degrees. All you have to do is adjust the scale.
Find this line:
var chart_size = "&chs=400x400&chtt=Eric's Office Temperature&chds=40,65&chxt=x,y,x,y&chxl=2:||Time (s)||3:|||Degrees (F)||&chxr=1,90,115|0,0,"+chartSec;
Change it to something like this:
var chart_size = "&chs=400x400&chtt=Eric's Office Temperature&chds=40,65&chxt=x,y,x,y&chxl=2:||Time (s)||3:|||Degrees (F)||&chxr=1,60,100|0,0,"+chartSec;