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