Here you go, http://www.mediacollege.com/audio/connection/xlr-jack-mono.html
Or, if you want to buy a ready made lead, something like this, http://www.amazon.co.uk/kenable-6-35mm-Socket-Microphone-Cable/dp/B003OSLUR2/ref=sr_1_3?ie=UTF8&qid=1428058502&sr=8-3&keywords=xlr+to+mono+jack
Or even one of these, http://www.ebay.co.uk/itm/XLR-FEMALE-Plug-To-6-35mm-Stereo-Jack-Socket-Microphone-Cable-Adapter-Adaptor-/400782214104