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)(11,16,18,13)(12,20,22,17)(19,21,24,23)(25,26)(27,34)(28,31)(29,36)(30,33)(32,38)(35,39)(37,40)(1,3,5,8)(2,6,4,7)(25,27)(26,30)(28,34)(29,35)(31,33)(32,39)(36,37)(38,40)(1,2,5,4)(3,6,8,7)(10,15)(11,18)(17,20)(19,24)(26,28)(27,33)(32,36)(35,40)(9,11)(10,16)(12,19)(13,15)(14,18)(17,23)(20,21)(22,24)(25,28,31,26)(27,34,33,30)(29,36,38,32)(35,37,40,39)(1,4,5,2)(3,7,8,6)(9,12,14,22)(10,17,15,20)(11,19,18,24)(13,21,16,23)(25,29)(26,32)(27,35)(28,36)(30,39)(31,38)(33,40)(34,37)(9,13,14,16)(10,11,15,18)(12,21,22,23)(17,19,20,24)(25,30,31,34)(26,33,28,27)(29,37,38,39)(32,35,36,40)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.