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