For European matches they tend to play at Stade Earnest Wallon. This is close to the main road junction alongside the Garonne Canal.
In previous years, they have laid-on a free Bus service from the Metro station (Barriere de Paris on the "yellow" Metro line) to just by the canal Bvd de Geneve- you have to walk alongside the canal to moveable bridge cross the canal then go under the road junction into the stadium car park.
An alternative if they aren't laying-on the bus and you have bought a transport pass (see below) is the L1 Bus from Jean Jaunes to Chem Roques (the walk is a bit longer than the other one)
The Toulouse Club shop is in the town centre close to Jean Jaures Metro/Bus interchange.
Do make use of their transport system. A three day pass, which allows travel on the Tram (from Palais de Justice, just north of the island which holds the TFC stadium where they also play, to the airport, and the Metro system and buses., is currently 13 euros, which is cheaper than buying a single day "tourist" pass which offers the same benefits!
If there is a Billets Jaune demo they tend to shut Metro stations between Jean Jaures abd Palais de Justice.,