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