Most 2 speed motors are '2 speed/1 winding' design...cheap to produce and easy to configure
Low speed and High speed tap into motor windings at different locations
Your drawing...
Hot comes into middle terminal of On/OFF/ON.
Top ON..power goes out Black for High
Bottom ON....power goes out RED for Low
Your 2 ON/OFF switches......
1 switch....Hot in/power out to Black (High)
1 switch....Hot in/power out to RED (Low)
ONLY one switch ON at a time........otherwise you are supply power to windings at same time/different locations and although motor may be at a 'middle speed' it was NOT designed to function in that mode.