The task ID is randomly generated and therefore it will not be possible to procedurally generate a URL to email to approvers. Additionally, the table that stores the those IDs is request_backend which does not also store data about the transaction that is meaningful to humans. So, in order to query the DB to get the ID it will require knitting together data from several sources and appears to be cumbersome. Without querying other DB tables first it isn't possible to know which ID you want from request_backend.
Having this functionality available out of the box would be considered an enhancement request.