How to design a big system diagram?

How to design a big system diagram?

Hey, 

we are implementing a huge CRM system including all our departments into the CRM, just like the new UI "CRM for everyone" motivates to do. 

We used Draw.io to predesign everything inside of a diagram. Something like blueprints, modules, custom fields, etc.

As the system gets bigger, it is getting harder to overview everything. Is there a tool that has prebuilt Zoho elements, just like Salesforce has for a lot of tools (Miro, Draw.io, ...)? 

What is the best way to design a huge implementation for Zoho CRM?

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