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