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