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