Vector graphics in a PDF may be displayed directly in a webpage by using SVG. Convert PDF to SVG by
inkscape in.pdf --export-plain-svg=out.svg
You can view
out.svg in any web browser, and zoom in virtually unlimited as it’s vector graphics like your original PDF diagram.
DraftSight outputs PDF even when EPS is selected. Convert PDF to SVG vector graphics for high resolution diagram on a webpage without download.