Visio is terrible at UML. Fortunately there are 3rd party stencils available which make it much better. Whatever you do, go for a drawing tool (Visio, Omnigraf

Visio is terrible at UML. Fortunately there are 3rd party stencils available which make it much better. Whatever you do, go for a drawing tool (Visio, Omnigraffle) and not a UML tool (Visual paradigm, Enterprise architect). The latter are too complicated and expect that the diagram is correct from a UML standard perspective, which unless you're generating code is useless and cumbersome to do.