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