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