Hi swtcyn -
Welcome to My Swiss Alps.
I don't recognize that beautiful lake, but perhaps one of our more experienced members may.
Is it one of the three lakes in the Piora Valley? This link could be a start:
If it is one of those lakes...and one of them (Lake Tom) seems to be about the right shape, then this map will show you where it is:
Zoom in and out, and switch back and forth between the map view and the aerial view.
You will see that the valley is located near Airolo, a town in the Gotthard pass. There is rail service and bus service. Icons on the map will show bus and train stations, as well as a lift or cable car up to the lakes from a town called Ambri-Piotta. (If you do not see icons for ststions, look in the menu under "points of Interest/Traffic" and turn on the icons.
And, this map give lots of details about the geography.
map.geo.admin.ch/?topic=ech&lang=en&bgLa yer=ch.swisstopo.pixel karte-farbe&layers=ch.bav.ha ltestellen-oev,ch.swisstopo.swiss tlm3d-wanderwege&layers_visi bility=false,false&X=1 56225.45&Y=696839.79&z oom=7
I do not guarantee that those lakes are the ones that you are looking for, but you did mention the name Piora Valley, so that is where I looked.
Lake Tom is at 2022 meters above sea level elevation.
I'll caution you that by the middle of October, at that altitude, you are just getting to the beginning of the Winter season in the high Alps, and it is possible that snow could block access . It looks like you might have to hike to reach it. It is about 3-4 km from the top station of the cable car, with a 200 meter or more altitude change.
From what town will you start your journey?
You can use the timetable to learn about travel times and schedules:
Ambri-Piotta station is about 2 1/2 hours by train from Zürich main station, or about 46 minutes from Bellinzona.
Snow in the Alps is not definite in mid-October, but it is quite possible. It is more likely the higher you are. Weather is highly dependent on altitude. Could you visit before your business trip?
This page, especially the links about weather and time of year will help you with your trip planning.
and www.myswissalps.com/ab outswitzerland
Follow the links...some are several layers deep.