Eagle
Jim,
I use the Eagle layout package for schematic generation and PCB layout. You can turn off the PCB stuff.
A freeware version is available at
http://www.cadsoftusa.com/freeware.htm
and runs under Mac as well as Linux.
I also googled 'free schematic software' and got several hits.
I don't know if I would characterize Eagle as particularly easy but its not too bad and there are tutorials available online. Like other capture/layout packages its component-object oriented i.e. everything on the sheet is a set of objects, a picture for the schematic, pin definitions and a PCB package (IC, relay outline etc). You get the components (switches, resistors, relays etc) out of a (pretty extensive) library, drop them on the sheet and hook em up with 'wires' (nets). Editing is pretty easy. As long as you don't care about a PCB layout (and you don't) , you just pick a symbol you like and use it. When you need something you don't have(no master contactors in the library), you can create it pretty easily.
I expect the foregoing is pretty much the same for any schematic capture package. The other freeware hits I got were for Windows..
The other route is something like AutoCAD lite or TurboCAD. Create the components you need and draw lines to connect. I've used both but prefer the schematic/PCB route. I'll put even one-off circuits on a PCB using one of the prototype houses like
www.4pcb.com rather than hand-wire it. Learning the schematic part of something like Eagle gets you halfway to that option.
If you decide to try Eagle, PM me and I'll dig out some objects I made for my wiring diagram(master contactors) and send em to you.
Others on the forum have published some pretty nice drawings as well. Hopefully they'll chime in with some other options.
Have fun.
John
