If, upon unboxing your Zynq-7000 AP SoC ZC706 Evaluation Kit, you note that the ATX (PCIe) MiniFit Jr. adapter was not included, you can request this to be sent to you directly.
Please open a Webcase with Xilinx Technical Support to receive this cable:
http://www.xilinx.com/support/clearexpress/websupport.htm; include your sales order number in the case notes. Please quote this Answer Record when opening the Webcase.
A workaround while awaiting the arrival of the ATX (PCIe) MiniFit Jr. adapter is to use the external 12V power brick to power the ZC706 externally when in the PCIe chassis.