One of the useful tool for visualization of RDF data is WebVOWL - http://visualdataweb.de/webvowl/. It supports RDF data in XML as well as in Turtle (TTL) formats and allows complex visualization of data.
There are seems to be also some tools to visualize data by accessing to a SPARQL endpoint (e.g. Apache Jena Fuseki provides the possibility to have a SPARQL endpoint, in addition to publicly available SPARQL endpoints, if that's of an interest). This might be a bit off-topic, but I hope at least related to your challenge :)
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WebVOWL seems to be indeed very useful and easy to use! Thanks for sharing!