"But yEd graph editor is not support to xml, so I need to convert XML into GraphML file then I can use that GraphML format in yEd graph editor."
Firstly yEd states:
"yEd can import data in various formats to generate diagrams out of it. Import formats include the Microsoft Excel .xls format for spreadsheet data, the Gedcom format for genealogical data, and also arbitrary XML-based file formats, which are transformed by means of XSLT stylesheets. Predefined XSLT stylesheets provided by yEd can process the Apache Ant build script format used to define dependency information in software build processes and the OWL file format for the description of ontologies. Other XML-based data is processed in a generic way."
I suggest you confirm this, and test to see if your XML can be used as an input. Had you super searched you'd have found nodes where people claim to have used yEd with XML, I dare say a google search would also be helpful.
Secondly, since you came to the conclusing that yEd didn't support xml, why did you choose it as the product to use in the first place?