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