Cause for Applause = Something worth Applauding = Some act that is worthy of praise. In the picture, you can see the audience applauding. The applause is most probably in praise of Creativity in the Orange County :)

You can approach it literally, a cause is something... well... a cause, I guess you can also put reason in there instead. So it's a reason to give a round of applause. In this case its the creativity (= the cause) which is worth the applause. Hope it helped