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