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