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