One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,4)(5,8)(6,7)(19,23)(21,24)(25,26,30,28)(27,31,33,34)(29,32,38,36)(35,39,37,40)(1,3)(2,6)(4,8)(5,7)(10,13)(14,16)(17,18,20,22)(19,21,23,24)(26,28)(27,33)(32,36)(35,37)(1,4,5,6)(2,7,8,3)(9,10,12,13)(11,14,15,16)(17,18)(19,21)(20,22)(23,24)(25,27)(26,31)(28,34)(29,37)(30,33)(32,40)(35,38)(36,39)(1,3)(2,4)(5,7)(6,8)(9,11,12,15)(10,14,13,16)(17,19)(18,21)(20,23)(22,24)(25,28,30,26)(27,34,33,31)(29,32,38,36)(35,39,37,40)(1,4)(2,7)(3,8)(5,6)(25,29,30,38)(26,32,28,36)(27,35,33,37)(31,39,34,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.