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