I went to a volvo dealer and purchased the correct vacuum "Coupling" - the one that is behind the power steering pump on my 1998 s70 non-turbo. For anyone reading this post who would like to replicate the purchase, the volvo part number is 9155862.

The photograph of the vacuum hose behind the power steering pump was very helpful. I found mine and it is cracked. Would someone be able to tell me the part number for a replacement? I don't want to pull the defective one without something in hand to put back on.