I don't think ColdFusion natively supports indenting xml/wddx. So either you can use xmlindent from cflib.org or if you are comfortable with java there are many solutions available see this thread like
Transformer transformer = TransformerFactory.newInstance().newTransformer();
// indent and omit xml declaration
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
StreamResult result = new StreamResult(new StringWriter());
DOMSource source = new DOMSource(doc);
transformer.transform(source, result);
return result.getWriter().toString();