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