Not from the model, but that is built into the diagram template definition. The concept of generate diagram is disconnect from the definition of what diagram type or template you want to generate against. When you configure your schematic dataset, you create a template (version 10), or a diagram type (pre-10). At that level of configuration you can specify a particular layout algorithm to be the default for that template. Then anyone generating a diagram (from engine, server, desktop, GP etc...) using that template will automatically get that layout applied.