Currently, Travis doesn’t have a way to display a build status badge for individual jobs in a matrix build. You can only get an individual badge which displays “passing” if all the jobs pass or “failed” if one job fails.
I’ve created a small open source web application which is deployable on Heroku. It can display build badges for matrix jobs like the following example:
Fork this project on Github: https://github.com/bjfish/travis-matrix-badges