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)(25,26,31,35)(27,37,29,33)(28,38,39,40)(30,36,32,34)(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)(26,33)(28,34)(29,31)(30,40)(32,38)(35,37)(36,39)(1,3)(2,5)(4,8)(6,7)(25,28,30,37,31,39,32,33)(26,27,34,40,35,29,36,38)(2,6)(3,8)(9,12,14,13)(10,16,17,22)(11,19,20,21)(15,23,18,24)(25,29,31,27)(26,33,35,37)(28,36,39,34)(30,38,32,40)(2,6)(5,7)(9,13,14,12)(10,16,17,22)(11,19,20,21)(15,24,18,23)(25,30,31,32)(26,34,35,36)(27,38,29,40)(28,33,39,37)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.