The closest campground is just a bit further down the Sibbald Creek Trail (Hwy 68) past the turnoff to the range - the Sibbald Lake Campground: http://www.bowvalleycampgrounds.com/cgrounds.html

There's an RV campground just west of the Calgary City limits at Calaway Park: http://www.calawaypark.com

Some provincial campground options further out toward Nakiska and K-country, further west of Calgary than the range: Kananaskis Country Campgrounds camping in Alberta

Book early as these fill up right away given it's Stampede time.