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