Actually if you want to collaborate efficiently among a team of developpers, I would recommend to use the embedded Git in Bonita Studio, available with Bonita Enterprise Edition.
You can use Bonita Studio on premise, and then install Bonita in a Cloud environment (AWS, Azure, other, or even bonita Cloud, as presented here). Bonita Studio is made to draw flows and is for the time being the only way to draw your diagrams.
Bonitasoft empowers development teams with Bonita, the open-source and extensible platform to solve the most demanding process automation use cases. The Bonita platform accelerates delivery of complex applications with clear separation between capabilities for visual programming and for coding. Bonita integrates with existing solutions, orchestrates heterogeneous systems, and provides deep visibility into processes across the organization.