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