What you are asking for is not possible unless
- you are using yEd, or
- you are using yEd Live, or
- you are using a custom application that was specifically developed to provide the features you are looking for.
Since you stated that you are not "a software genius", I take it you are not software developer/programmer. This means option 3 is not for you.
Since you "can't bother your boss or clients to work with graphml files", I take it you mean you cannot ask your boss and/or clients to use yEd. This means option 1 is not for you either.
This leaves you with option 2. While strictly speaking this is asking your boss/clients to "work with graphml files" as well, they can do so from within their preferred internet browser which might be less of an obstacle than having to install yEd.