The version of "Exodus" you uploaded to to Piano Society originated as an Ampico Piano Roll whose file was scanned by computer, and subequently converted to a MIDI file and played back on a rather cheap sounding electronic piano. The analog outputs of the electronic piano sound were converted to the .wma file you have heard.
Upon closer listening inspection, you will determine that -- as is -- the exact piano roll performance is impossible to be played in real time by just one person: much of the right hand is doubled in high octaves, and the left hand part is actually two separate parts, with simultaneous octave bass playing along with full chords.
If you perform an internet Google search according to "Exodus 41121", you will learn that this rendition of 'Exodus' was played by Bud Noble (from a QRS CEL-186 piano roll). From there, it is possible to find and download the actual midi file, and then convert it to musical notation via Finale, Sibelius or some other suitable notation software.
P.S. I would be able to trascribe a somewhat playable version for you, as I possess absolute pitch and can transcribe this music. However, until such time that this performance can be deemed as being in the public domain, I am hesitant to do so for obvious copyright infringement considerations.