The DIAGRAM-INFO slot is probably not what you are looking for -- it is only populated for signaling pathways, whose layout is generated manually by a curator (our automated pathway layout algorithms don't work for signaling pathways). This slot stores enough info for the software to regenerate the curator-specified layout. There are a small number of such signaling pathways (in EcoCyc, HumanCyc and I think BsubCyc) that use this slot, but the vast majority of pathways have their layouts computed without manual oversight by our automated pathway layout algorithms. This enables them to automatically adapt to changes in the database, and be displayed at varying levels of detail (neither of which are possible for the signaling pathways), but it means that because the layout is computed afresh each time, very little layout information needs to be stored in the pathway frames themselves (the LAYOUT-ADVICE slot allows curator specification of some minor points such as which compound should be displayed at the top in a circular pathway). Our automated layout algorithms are quite complex, so you are unlikely to be able to regenerate them. We do use Grasper-CL as our underlying graph toolkit, but the grasper graphs are generated on demand, and are not stored anywhere (an exception is the cellular overview diagram -- since this diagram is too time-consuming to regenerate each time, the grasper graph is stored as a file).
If you are trying to extract node/edge coordinates, labels, etc. for our diagrams, the following two options are available at this time: If you export a pathway to a pathway collage, you can save the collage to a file that contains a JSON representation of the pathway graph. Alternatively, we have a couple of unpublicized lisp functions (accessible via the Lisp API) to export one or all pathways to XGMML format files. If you request our source code, you'll find the relevant functions in the file pwy2xgmml.lisp (if you would prefer the diagram in grasper format, and are comfortable with lisp programming, there are useful functions for that in this file also).
