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