Assuming the following in Central Texas (from a retail standpoint, not cost to contractor):

Cost of Concrete: $75/cu yd @ 4yrds = $300
Cost of coloring or cool decking applied to concrete: $4/sq ft x 240 sq ft = $960
Labor at $7/sq ft to form, place and finish concrete: $7/sq ft x 240 = $1,680

Total = $2,960

Turnkey might be a little more, +/- 10% markup and you will be at roughly $3,250K

Absent being in Maui, here in Central Texas this project would run between $3K and $3.5K. Albeit that is for cool decking (assuming you were putting it around a pool), for just stained or colored concrete you might reduce you cost by a couple dollars per square ft, but the cost of material and labor would remain about the same. At the end of the day depending upon your finish of the concrete, you are looking at $10 - $14/sq ft (With $10 being close to minimum)