Hi Mariia,
We have prepared a separate CRUD sample with reset button for your requirement and please refer to the sample from the link below,
When you are clicking on the reset button, if there are no nodes and connectors in the diagram then it will reset the diagram in the current sample and it will reflect the same in the live sample browser as well.
We will consider to provide the reset option to the live CRUD sample browser itself in our upcoming release.
Regards,
Gowtham