可以试试ProcessOn.com, 一个专业在线画流程图的工具，使用Chrome&Firefox浏览器，支持快捷键，非常方便。
快捷键如下：
Ctrl+A 全选，当移动整张图时非常方便
Ctrl+B 格式刷，选中图形A,按Ctrl+B,选中图形B，则对图形A的设置会应用到图形B上
Graphviz - Graph Visualization Software
Graphviz的是AT&T Labs Research开发的图形绘制工具,他可以很方便的用来绘制结构化的图形网络,支持多种格式输出,生成图片的质量和速度都不错.
Graphviz本身是开源的产品,下载可以到 这里,以及他的演示界面 Graphviz在windows上和Linux上都可以顺利运行.
Welcome to Graphviz
What is Graphviz?
Graphviz is open source graph visualization software. Graph visualization is a way of representing structural information as diagrams of abstract graphs and networks. It has important applications in networking, bioinformatics, software engineering, database and web design, machine learning, and in visual interfaces for other technical domains.
Features
The Graphviz layout programs take descriptions of graphs in a simple text language, and make diagrams in useful formats, such as images and SVG for web pages; PDF or Postscript for inclusion in other documents; or display in an interactive graph browser. Graphviz has many useful features for concrete diagrams, such as options for colors, fonts, tabular node layouts, line styles, hyperlinks, and custom shapes.
Roadmap
dot - "hierarchical" or layered drawings of directed graphs. This is the default tool to use if edges have directionality.
neato - "spring model'' layouts. This is the default tool to use if the graph is not too large (about 100 nodes) and you don't know anything else about it. Neato attempts to minimize a global energy function, which is equivalent to statistical multi-dimensional scaling.
fdp - "spring model'' layouts similar to those of neato, but does this by reducing forces rather than working with energy.
sfdp - multiscale version of fdp for the layout of large graphs.
twopi - radial layouts, after Graham Wills 97. Nodes are placed on concentric circles depending their distance from a given root node.
circo - circular layout, after Six and Tollis 99, Kauffman and Wiese 02. This is suitable for certain diagrams of multiple cyclic structures, such as certain telecommunications networks.
http://www.graphviz.org/