A novel methodology has been developed to capture student interactions and engagement modes by mapping their discourse in Process Oriented Guided Inquiry Learning (POGIL) physical chemistry courses using graph theory and a modified ICAP ("Interactive," "Constructive," "Active," "Passive") framework. This work provides a deeply contextualized description of student teamwork in a POGIL setting with triangulation of data from talk-turn tracking and coding of student engagement. Graphs of student discussions in teams were constructed for 17 students in five teams in two courses taught by different instructors. Combined with the modified ICAP framework, our data illustrate the amount, extent, and quality of discussion along with students' cognitive engagement. Specific facilitation strategies used by instructors appear to correlate with improved student discussion and interactivity. Such strategies include providing responsive versus prepared lectures and requiring students to publicly share their thinking.