One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,7)(4,6)(5,8)(9,10)(11,18)(12,16)(13,23)(14,17)(15,21)(19,24)(20,22)(25,26,30,34)(27,35,37,32)(28,31,33,29)(36,40,39,38)(1,3,4,8)(2,5,6,7)(9,11,14,21)(10,15,17,18)(12,22,23,19)(13,20,16,24)(25,27,30,37)(26,32,34,35)(28,38,33,40)(29,36,31,39)(9,12,14,23)(10,16,17,13)(11,19)(15,24)(18,20)(21,22)(25,28,31,34,30,33,29,26)(27,35,36,38,37,32,39,40)(2,6)(5,7)(9,13,14,16)(10,12,17,23)(11,20,21,24)(15,22,18,19)(25,29,30,31)(26,33,34,28)(27,36,37,39)(32,40,35,38)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.