Revision 40f19aca-541f-4b32-b572-d2901e13e4e6 - Code Golf Stack Exchange

# [C (gcc)], 171 bytes

<!-- language-all: lang-c -->

 #define r rand()
 i;m;b;q(){for(m=0,i=1;i<5;i++)m|=!!(r%9)<<i;m||q();}f(){q();for(b=(r%4+1)*5;--b;)printf(b%5?m&1<<b%5?"%c%c":"--":(":"+!q()),"RWSC"[r%4],"urgbypcw"[r%8]);}

[Try it online!][TIO-ksrui9cl]

[C (gcc)]: https://gcc.gnu.org/
[TIO-ksrui9cl]: https://tio.run/##HY7BboMwEETvfIVxROUtWAKpSG3WKIf@QXLooeKAHYws1TRxiFAV8utxlp52dveNZowcjIlxc@ytG3sWWOjGo4DEoUeNZwE3@xuEb8rCNRU6VaPLc/BLk6YiZB@gFJHLQiDeLdGrWB26ofdbXsFrjVJqhFNw42SFzuqdf6mUWgXPTGb4lkvJt4JmnpIdCr7/Onzyb/K3Bb@GQf@dzLzu7y2lRN@5UQC7JYxd/ttOzveiBEC6UAdM7vFh7E83XKKcnw "C (gcc) – Try It Online"