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