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)(11,14)(12,15)(13,16)(17,24)(18,22)(19,21)(20,23)(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)(10,14)(12,19)(13,18)(15,21)(16,22)(17,20)(23,24)(25,27,30,37)(26,32,34,35)(28,38,33,40)(29,36,31,39)(9,12,13,20)(10,15,16,23)(11,17)(14,21)(18,19)(22,24)(25,28,31,34,30,33,29,26)(27,35,36,38,37,32,39,40)(2,6)(5,7)(12,20)(15,23)(17,19)(21,24)(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.