SetVertexPositions('G', 'vp') sets the vertex positions vp of the graph G for graph drawing.  The vertex positions should be input in the format [[x1,y1],[x2,y2],...,[xn,yn]] or [[x1,y1,z1],[x2,y2,z2],...,[xn,yn,zn]].

$\mathrm{with}\left(\mathrm{GraphTheory}\right)\:$

$G≔\mathrm{Graph}\left(6\,\left\{\left\{1\,2\right\}\,\left\{1\,4\right\}\,\left\{2\,3\right\}\,\left\{2\,5\right\}\,\left\{3\,6\right\}\,\left\{4\,5\right\}\,\left\{5\,6\right\}\right\}\right)$

$G≔\mathrm{Graph\; 1:\; an\; undirected\; graph\; with\; 6\; vertices\; and\; 7\; edge(s)}$

$\mathrm{DrawGraph}\left(G\right)$

$\mathrm{vp}≔\left[\left[0\,0\right]\,\left[0.5\,0\right]\,\left[1\,0\right]\,\left[0\,0.5\right]\,\left[0.5\,0.5\right]\,\left[1\,0.5\right]\right]\:$

$\mathrm{SetVertexPositions}\left(G\,\mathrm{vp}\right)\:$

$\mathrm{DrawGraph}\left(G\right)$

The GraphTheory[SetVertexPositions] command was updated in Maple 2020.