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