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