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