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