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