Since 1875, Frederick Field’s edition of Origen’s Hexapla has been the standard reference for the work. A new edition is in preparation under the auspices of the Hexapla Project. But, for the present, Field’s work remains an invaluable resource. His two-volume edition is available via Internet Archive.
N.B.: The Internet Archive link in the Hexapla Project’s “Editions of the Hexaplaric Fragments” goes only to a page that provides only Field’s first volume, containing Genesis–Esther. The second volume, containing Job–Malachi, is available on a separate page.