function createGraphvizOptions(config) {
	const graphVizOptions = config.graphVizOptions || {};

	return {
		dotCommand: config.graphVizPath ? config.graphVizPath : null,
		attributes: {
			// Graph
			graph: Object.assign({
				overlap: false,
				pad: 0.3,
				rankdir: config.rankdir,
				layout: config.layout,
				bgcolor: config.backgroundColor
			}, graphVizOptions.G),
			// Edge
			edge: Object.assign({
				color: config.edgeColor
			}, graphVizOptions.E),
			// Node
			node: Object.assign({
				fontname: config.fontName,
				fontsize: config.fontSize,
				color: config.nodeColor,
				shape: config.nodeShape,
				style: config.nodeStyle,
				height: 0,
				fontcolor: config.nodeColor
			}, graphVizOptions.N)
		}
	};
}
Return options to use with graphviz digraph.
@param  {Object} config
@return {Object}