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