You can find a PDF file of the schematics on the MPC8313E-RDB Board Support Package and Documentation CD that came included when you bought your board.
For version A of that CD, the file is /Document/MPC8313ERDBGS_Apr2007
If you have a newer board, it may be a different filename, but I assume you'll still find it in that directory on the CDROM.
As far as a PCB board document goes, Freescale gives you a high level one describing features, conntectors, dip switches etc. but they do not give you detailed gerber files either on the CDROM or publicly downloadable. If you need that level of documentation, you'll have to try and get that from your Freescale salesperson, assuming they even can give/sell them to you.
Hope this helps,
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