可以試試ProcessOn.com, 一個專業線上畫流程圖的工具，使用Chrome&Firefox瀏覽器，支援快捷鍵，非常方便。
快捷鍵如下：
Ctrl+A 全選，當移動整張圖時非常方便
Ctrl+B 格式刷，選中圖形A,按Ctrl+B,選中圖形B，則對圖形A的設定會應用到圖形B上

Graphviz - Graph Visualization Software

Graphviz的是AT&T Labs Research開發的圖形繪製工具,他可以很方便的用來繪製結構化的圖形網路,支援多種格式輸出,生成圖片的質量和速度都不錯.

Graphviz本身是開源的產品,下載可以到 這裡,以及他的演示介面 Graphviz在windows上和Linux上都可以順利執行.

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/