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