ArcObjects Developer Kit\Samples\ArcMap\Layers\Create Layer Files
ArcObjects Developer Kit\Samples\ArcMap\Layers\Add Layer from File.
См. также ArcObjects Developer Kit\Samples\ArcMap\Symbology\Renderers\FeatureClassDraw
для растров:
ArcObjects Developer Kit\Samples\Raster\CopyRasterSymbologyBetweenLayers