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