Hi @Bocian1,
In that case you can for example use a list groups. With an OData Filter you can even find the specific group in that action. That action should output the correct group and its id.
Below is an updated example
1. List Groups with filter on displayName property
displayName eq 'SPO Task Linking'
2. URI which used the id of the first returned group
https://graph.microsoft.com/v1.0/groups/@{first(outputs('List_groups')['body']['value'])['id']}/sites/root?$select=webUrl
