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