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