Galaxy wrapped version of the Circos tool: Graph/Display Data > Circos Builder creates circos plots from standard bioinformatics datatypes
Help for the underlying Circos tool is here (also linked from the Galaxy tool form): http://circos.ca/documentation/
Specifically, see this section. The UCSC Table browser can be queried directly from within Galaxy with the tool Get Data > UCSC Main or obtain the data from the UCSC Downloads area at http://genome.ucsc.edu and upload it to Galaxy (use FTP for any data over 2 GB in size https://galaxyproject.org/support/loading-data/).
CREATING YOUR OWN IMAGE The first thing you will need is the karyotype for your genome. The karyotype defines the chromosomes (name, size, color) and, optionally, the cytogenetic band pattern. You can obtain karyotypes for many genomes from the cytoBandIdeo table (UCSC genome browser).
You can download the karyotype from the table browser or directly for human hg19 (Feb 2009) hg18 (Mar 2006), mouse mm9 (Jul 2009) mm8 (Mar 2006), rat rn4 (Nov 2004) rn3 (Jun 2003), or other species.
Thanks! Jen, Galaxy team