If you are new to digital printing, I'll offer a suggestion that might seem excessive, in response to just today's color matching issue... but it may well help you with that, AND will most certainly come in handy again & again for reasons I'll get into below.
My suggestion is to locate a cmyk color chart that you can print a very good sized resource on your printer, to help you with color matching on into the future.
I just went and found one such chart available for download, and you can easily find many more, but here is that link:
http://www.ocp.de/documents/OCP_CMYK_Chart.pdf
Be sure to note all the setting that might change from day to day, like how many passes, or ink layers, or speed, resolution, profile or whatever setting your equipment and software offer... not those settings (perhaps incorporating them onto the header of the print, so it's always right there,,, and not the media you choose to print this chart on. If like me, you primarily print Orajet 3651, banner media, and 3M 180C.... you could eventually find value in printing a chart on each of the common media you may use...
Then I guess it's pretty obvious that you can get a swatch of 3M vinyl, and compare your clients desired media, to YOUR chart, printed on YOUR printer, with all the settings noted... so if you do find a match, you can just use that color from the swatch...
The other type of benefits I said I'd get to, is that if you have a showroom/shop where clients come in and order signs... when they don't have pantone swatch numbers (of vinyl color codes) you can just have them choose off your chart & then you should be able to give fairly consistent matches