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