Are there any tools for visualizing code complexity or graphing method calls in Objective-C?

AnalysisTool: I know it's a clang wrapper but it also provides dependency diagrams.

AnalysisTool was originally created to serve two main purposes: to provide an easy-to-use executable binary of Clang static analyzer and to customize Clang by providing some additional checks. When Clang static analyzer was in its early stages, the only option for developers to try it out was to check out the latest source code of LLVM and Clang, compile it, and use the analyzer from the command line. AnalysisTool provided an easy-to-use GUI interface and removed the need to touch Clang source code. It also provided automatic updates, so that users of AT could always use the latest Clang static analyzer.

lizard:

This tool will calculate the cycolomatic complexity of C/C++/Objective C code without caring about header files and preprocessors. So the tool is actually calculating how complex the code 'looks' rather than how complex the code 'is'.

People will need this tool because it's often very hard to get all the include folders and files right with a similar tool, but we don't really need that kind of accuracy when come to cyclomatic complexity.

These are the only two tools I know, hope this helps.