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