Although the diagramming issue has long ceased to be an important topic of discussion or research (after all, you can easily 'translate' labelled brackets, trees, boxes, relational igloos, feature structures, relations, functions, etc. into each other and find ways to prove that they are mathematically equivalent), I think you could still benefit from reading at least the following (oldish) books:
Edith A. Moravcsik & Jessica Wirth, eds., 'Current Approaches to Syntax'(Syntax and Semantics volume 13), New York, Academic Press 1980. (With info on practically all approaches to syntax still alive ca. 1980)
Peter Sells, 'Lectures on Contemporary Syntactic Theories', Stanford, CSLI, 1985 (good for GB vs. LFG and GPSG)
Stuart M. Shieber, 'An Introduction to Unification-Based Approaches to Grammar' (CSLI Lecture Notes, 4), Stanford, CSLI, 1986. (good for LFG, GPSG, HPSG)
Giorgio Graffi, '200 Years of Syntax. A Critical Survey', Amsterdam & Philadelphia, John Benjamins, 2001. (A generally informative overview of syntactic theory and analytical techniques, including diagramming, since the early 19th c. to the late 1990's).