When catching a swing kick many fighters are taught to catch over the kick with the same side arm and expose their ribs in the process. A good opponent will pick up on this and continue to kick your ribs, no matter if you catch it or not, in turn causing damage.
A better way to catch a swing kick is to create a shield with your same side arm and come under the kick with your opposite hand to catch it against your shield arm. We also have a drill for evading and countering swing kicks.
You can then swing the leg through, closing off your opponents body so they can not attack you. From here you have free range to open up with a combination without worrying about being attacked, as your opponent is out of position.
There are many different ways to catch, counter, or evade swing kicks. One should not be taken as the right or the wrong way.
In my opinion it is best to have many different defensive tactics to each weapon being thrown at you. Then you can consistently change these defensive tactics and not allow your opponent to create a plan to beat one.
For more in depth analysis check out The Ultimate Guide to Striking for MMA, Muay Thai and Kickboxing.