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)(11,15,18,14)(12,20,22,16)(19,23,21,24)(25,26)(27,39)(28,34)(29,35)(30,37)(31,36)(32,38)(33,40)(9,11,13,18)(10,14,17,15)(12,21,22,19)(16,24,20,23)(25,27,32,28)(26,33,38,29)(30,40,31,35)(34,36,39,37)(1,3,5,4)(2,6,7,8)(9,11)(10,15)(12,19)(13,18)(14,17)(16,24)(20,23)(21,22)(25,28,32,27)(26,34,38,39)(29,37,33,36)(30,40,31,35)(1,4,5,3)(2,6,7,8)(11,18)(14,15)(19,21)(23,24)(25,29)(26,35)(27,36)(28,37)(30,34)(31,39)(32,33)(38,40)(9,12,13,22)(10,16,17,20)(11,19,18,21)(14,23,15,24)(25,30,32,31)(26,36,38,37)(27,40,28,35)(29,34,33,39)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.