Question: How to make box shaped nodes to circle shaped in Graph plot

I found some codes for drawing my Graph in Maple:

[>  with(GraphTheory);

     W := Graph(undirected, {{0, 1}, {0, 2}, {0, 3}}):

     HighlightEdges(W, W, black):

     HighlightVertex(W, [1, 2, 3, 0], gray):

     DrawGraph( W);

 The way that the graph was plotted was not what I wanted to have. In fact, I expected to have something like this one:

http://i.stack.imgur.com/JMfmd.png

I mean the vertexes are shaped by circles not by boxs. Moreover, one may want to see labels below (or above) the circled nodes. My question is 

" Is there any certain codes we can use to have this graph like the picture above? Can we manage the labels to be appeared near the nodes in Maple?

Thanks for your time!

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