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