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