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