The power symbols are hidden in the IEEE symbols.
To make visible, choose which of the six inverters you wish to show pins 14 & 7.
Open your Symbol Editor and place the unit from the 7406 you wish to show the power pins in the editor.
You will notice the writing and small circle (top and bottom centres of the outline) in blue.
Right mouse click in or just above/below each blue circle outside the box. This opens the pin properties.
Above the preview box in properties click “visible”… Done.
To create personal libraries follow this and then this. Both are in the FAQ at the top of this page.
When you have your own libraries you can copy the 74LS06 into your personal library and then just re-name it to 7406 and you will have the 7 parts with the triangular inverters.
If you want instructions for this please ask.
You can also just re-name the 74LS06 to 7406 by changing its Value after you have placed the gates on the schematic but this is not great practice as it only shows on this schematic and is tedious as every gate will need to be altered.