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