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